#!/bin/bash

# -------------------------------------------------------------------------- #
# Copyright 2002-2023, OpenNebula Project, OpenNebula Systems                #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #

# snap_create host:parent_image snap_id vmid ds_id

SRC=$1
SNAP_ID=$2
VMID=$3

if [ -z "${ONE_LOCATION}" ]; then
    TMCOMMON=/var/lib/one/remotes/tm/tm_common.sh
else
    TMCOMMON=$ONE_LOCATION/var/remotes/tm/tm_common.sh
fi

DRIVER_PATH=$(dirname $0)

. $TMCOMMON

SRC_PATH=$(arg_path $SRC)
SRC_HOST=$(arg_host $SRC)

#-------------------------------------------------------------------------------
# Get Image information
#-------------------------------------------------------------------------------

DISK_ID=$(basename ${SRC} | cut -d. -f2)

XPATH="${DRIVER_PATH}/../../datastore/xpath.rb --stdin"

unset i j XPATH_ELEMENTS

while IFS= read -r -d '' element; do
    XPATH_ELEMENTS[i++]="$element"
done < <(onevm show -x $VMID| $XPATH \
                    /VM/TEMPLATE/DISK\[DISK_ID=$DISK_ID\]/FORMAT)

FORMAT="${XPATH_ELEMENTS[j++]}"

SYSTEM_DS_PATH=$(dirname ${SRC_PATH})

DISK_PATH="${SYSTEM_DS_PATH}/disk.${DISK_ID}"

SNAP_DIR="${DISK_PATH}.snap"
SNAP_DIR_SHORT=$(basename "$SNAP_DIR")

SNAP_PATH="${SNAP_DIR}/${SNAP_ID}"
SNAP_PATH_SHORT="${SNAP_DIR_SHORT}/${SNAP_ID}"

if [ "$FORMAT" = "qcow2" ]; then
    SNAP_CMD=$(cat <<EOF
        set -e -o pipefail

        if [ -f "${SNAP_PATH}.current" ]; then
            CURRENT_PATH=\$(cat "${SNAP_PATH}.current")
            CURRENT_ID="\${CURRENT_PATH##*/}"

            SNAP_PATH_SHORT="${SNAP_DIR_SHORT}/\${CURRENT_ID}"
        else
            SNAP_PATH_SHORT="${SNAP_DIR_SHORT}/${SNAP_ID}"
        fi

        cd "${SNAP_DIR}"
        qemu-img create -f qcow2 -o backing_fmt=qcow2 \
            -b "\${SNAP_PATH_SHORT}" "\$(readlink -f ${DISK_PATH})"
EOF
)
else
    SNAP_CMD=$(cat <<EOF
        set -e -o pipefail

        rm "${DISK_PATH}"
        cp "${SNAP_PATH}" "${DISK_PATH}"
EOF
)
fi

ssh_exec_and_log "${SRC_HOST}" "${SNAP_CMD}" \
                 "Error reverting snapshot to ${SNAP_PATH}"
